The global environment has been worsening seriously in recent years, and each country has been taking environmental measures. Under such circumstances, an energy generation method using renewable energy, such as solar energy, wind energy, geothermal energy (hereinafter, referred to as the renewable energy generation method), and an energy generation method using environmentally friendly resources, such as biomass energy, fuel cell, and the like (hereinafter, referred to as the environmentally friendly energy generation method) are drawing a great deal of attention. At present, a thermal energy generation method using fossil fuels, such as oil, coal, and the like, a nuclear energy generation method using atomic energy, and a hydroelectric energy generation method using flowing water are mainly used.
The nuclear energy generation method is an environmentally friendly energy generation method, but has difficulties and risks in the safety of managing atomic fuels. The hydroelectric energy generation method is also environmentally friendly; however, only areas with geographical conditions suited for constructing dams, or the like, can utilize this method. The thermal energy generation method is facing problems, such as the drain of fossil fuels, emissions of CO2, NOx, and the like, generated from burning fossil fuels. In light of the circumstances, replacing the thermal energy generation method with the renewable energy generation method or the environmentally friendly energy generation method is under discussion.
In recent years, individual electric energy consumers have become more conscious of global environmental issues, and there is a movement to use an energy generator to implement the renewable energy generation method or the environmentally friendly energy generation method (hereinafter, referred to as a green energy generation apparatus) in a household. Further, in order to resolve problems of instability in the supply of energy, which is a weak point of the renewable energy generation method, there is also a movement to use an electric storage apparatus in a household along with the energy generator implementing the renewable energy generation method. In other words, individual electric energy consumers are obtaining the green energy generation apparatus and the electric storage apparatus for their households at a rapid pace. In the near future, a greater number of individual electric energy consumers will generate electric energy in their households, and cover their own consumption with the electric energy they generate themselves.
At present, electric utility companies are buying the surplus electricity that individual electric energy consumers generate but cannot consume themselves. However, for the electric utility companies, the electricity generated by individual electric energy consumers is an unstable energy source, the capacity and timing of supply being unpredictable. Such electricity is not attractive for the electric utility companies, so the prices of electricity sold to electric utility companies from individual electric energy consumers tend to be low. The amount of electricity produced by each of the individual electric energy consumers is extremely small compared to the capacity currently traded in the energy trading market; therefore, individual electric energy consumers cannot sell the electricity in the energy trading market in the present situation.
Further, the existing energy trading market comprises limited players. In fact, it is practically impossible for individual electric energy consumers to trade in the energy trading market. Regarding electricity trading, Japanese Unexamined Patent Application Publication No. 2008-225755 discloses a method for predicting precisely the amount of electricity to sell and to buy based on past trading history in the energy trading market. Regarding the structure of the current electricity trading, information distributed from the Japan Electric Power Exchange, the Chicago Mercantile Exchange (CME), or the like, must be useful.